To investigate biomarkers representing the physiological and biochemical responses of the brackish-water clam Corbicula japonica, we conducted a full factorial-design experiment to test different water-temperature levels (20 °C and 25 °C), salinity levels (5 and 20 psu), and food-availability levels (0.5 and 2.0 mg suspended solids (SS)·ind⁻¹·d⁻¹). Increase in water temperature significantly decreased superoxide dismutase (SOD) and catalase (CAT) activities and oxyradical-absorbance capacity (ORAC), leading to lipid peroxidation (i.e., oxidative damage). Salinity activated or inhibited these biochemical markers. Food availability supported a detoxification mechanism against oxidative stress. Principal-components and cluster analyses revealed that a total of eight experimental conditions fell into three groups related to water temperature and/or salinity. The shift from Group I (20 °C water temperature) to Group II (25 °C water temperature and 5-psu salinity) demonstrated that the condition index, SOD, CAT, and ORAC had significantly decreased. With the further shift to Group III (25 °C water temperature and 20-psu salinity), we found a prominent increase in ORAC, which led to oxidative damage but no mortality. We conclude that future habitat changes driven by global warming should be closely watched, particularly given that local anthropogenic disturbances further add to natural ones.

Copper pollutions are typical heavy metal contaminations, and their ability to move up food chains urges comprehensive studies on their effects through various pathways. Currently, four exposure pathways were prescribed as food-borne (FB), water-borne plus clean food (WCB), water–food-borne (WFB) and water-borne (WB). Caenorhabditiselegans was chosen as the model organism, and growth statuses, feeding abilities, the amounts of four antioxidant enzymes, and corresponding recovery effects under non-toxic conditions with food and without food were investigated. Based on analysis results, copper concentrations in exposure were significantly influenced by the presence of food and its uptake by C.elegans. Both exposure and recovery effects depended on exposure concentrations and food conditions. For exposure pathways with food, feeding abilities and growth statuses were generally WFB<WCB⩽FB (p<0.05). The antioxidant activities were up-regulated in the same order. Meanwhile, the exposure pathway without food (WB) caused non-up-regulated antioxidant activities, and had the best growth statuses. For recoveries with food, growth statuses, feeding abilities and the inductions of the antioxidant enzymes were all WB≈WFB<WCB<FB (p<0.05). For recoveries without food, the order of growth statuses remained WB>FB>WCB>WFB (p<0.05), while the antioxidant activities were all inhibited in a concentration–dependent fashion. In conclusion, contaminated food was the primary exposure pathway, and various pathways caused different responses of C.elegans.

Copper is an essential element and also produces adverse health consequences when overloaded. Food and water are the main sources of copper intake, however few studies have been conducted to investigate the difference between the ways of its intake in water and food in animals. In this study, copper was fed to mice with food as well as water (two groups: water and diet) for three months at concentrations of 6, 15 and 30 ppm. The copper concentration in water was adjusted for keeping the same amount during its intake in food. The experimental studies show a slow growth rate, lower hepatic reduced glutathione (GSH)/superoxide dismutase (SOD) activity and higher serum ‘free’ copper in the water group. The brain's soluble amyloid-beta 1-42 (Aβ₄₂) of the water group was significantly higher than that of the diet group at the levels of 6 and 15 ppm. In conclusion, copper in the water group significantly increased the soluble Aβ₄₂ in the brain and the ‘free’ copper in the serum, decreased the growth rate and hepatic GSH/SOD activity. The research studies carried out suggest that the copper in water is more ‘toxic’ than copper in diet and may increase the risk of Alzheimer's disease (AD).

It is well known that immune defenses of bivalves against environmental and pathogenic stresses are primarily attributable to hemocytes. Hemocyte parameters are being used progressively as indicators to assess the host immune status. Moreover, there is increasing evidence that seasonal variations on the immune status have two origins: exogenous and endogenous. In this work, we investigated the effects of seasonal exogenous (water temperature and food availability) and endogenous (size and reproduction) factors on the hemocyte parameters in the scallop Chlamys farreri. Scallops were monthly collected from February to December 2009 at 2 sampling sites differing in culture mode: Qingdao for monoculture and Weihai for scallop—kelp polyculture. Six hemocyte parameters including total hemocyte count (THC), granulocyte percentage (GP), intrahemocytic phenoloxidase (PO), acid phosphatase (ACP), superoxide dismutase (SOD), and peroxidase (POD) were analyzed. Results illustrated that all hemocyte parameters exhibited marked seasonal variations, following a similar pattern at both sites. High values of THC, GP, PO, and POD were observed in spring and early summer, a period of favorable water temperature and high food availability and gonad index, whereas low values were found in summer and early autumn, a period corresponding to reproduction completion and high water temperature. Moreover, SOD was lowest in February and highest in August, and correlated positively with water temperature. Hemocyte parameters in the scallop C. farreri varied greatly among seasons, and their values were generally low during summer and early autumn, suggesting that scallops had a depressed immune status during this period.

Food and water are closely associated with reproductive willingness in vertebrates. These are important for animals and their non‐availability act as stressors which decrease sex steroid secretion suppressing reproductive behaviour. Oestrogen plays a crucial role in reproduction via its receptors alpha (ERα) and beta (ERβ). This study tested the hypothesis that ERα in testes of male Japanese quail is regulated during water and food deprivations. The present study reveals that both water and food deprivations cause oxidative stress and subsequently decrease catalase and superoxide dismutase activity, while these increase malondialdehyde and hydrogen peroxide. Both deprivations reduce plasma oestradiol whereas elevate corticosterone level. The immunofluorescent localization of ERα in the testes occurs predominantly in the seminiferous tubules of control while reduces after both food and water deprivations. All types of spermatogenic cells were seen in control testis, while after water and food deprivations size of seminiferous tubules and spermatogenic cells population decreased. Scanning electron microscopic study exhibited fully mature sperms in clusters with head and elongated flagellum, whereas after water deprivation maximum sperms were distorted, scattered with highly reduced head. On food deprivation, only few sperms were seen with head and tail. Thus, taking into account the localization of ERα in testis, it is obvious that oestrogens produced locally are involved in regulation of spermatogenesis and spermiogenesis during stress.